It is conventional to form a through hole in a beam of a building structure to let pipes and wires to pass through the beam. In this case, the flexural strength of the beam decreases because of the through hole. To prevent this decrease in the flexural strength of the beam, a beam reinforcing metallic material is connected to the beam, reinforcing the same.
As such a beam reinforcing metallic material, there is a method, for example, in which a plate being shaped to fit along the through hole is connected around the through hole (Patent Document 1 for example).